C - Reactive Protein Levels in Patients with Periodontal Disease and Normal Subjects

Although periodontitis is a chronic inflammatory disease but some factors of acute inflammation phase are involved in this disease among which is the C-Reactive protein (CRP). To minimize its effects, anti-inflammatory drugs or non-pharmacological approaches such as oral hygiene is recommended. CRP can also be used for the prediction and early detection of periodontal disease. The aim of the present study was the comparison of the amount of salivary C-Reactive protein (CRP) in healthy subjects and patients with periodontal disease. This case-control study was done on 90 patients referred to the Department of Periodontology of Babol Dentistry School. These subjects were divided into three groups of healthy (n = 30), gingivitis (n = 30), and chronic periodontitis (n = 30), based on Gingival Index (GI) and Clinical Attachment Loss (CAL) indices. 2ml saliva samples were collected from these people and clinical indicators including GI, CAL, Periodontal Pocket Depth (PPD), and Bleeding Index (BI) were assessed. ELISA method was used to evaluate the salivary CRP levels. Collected data were analyzed using SPSS statistical software by non-Parametric Kruskal-Wallis and Mann-Whitney test and Spearman correlation coefficient and P<0.05 was considered significant. The mean salivary CRP levels were 5332.62±5051.63pg/ml in periodontitis patients, 3545.41±3061.38pg/ml in gingivitis group and 3108.51±3574.47pg/ml in healthy subjects. The statistic analysis showed a significant difference in salivary CRP concentrations between the periodontitis patients and healthy subjects (P=0.045). The results indicate that there is a significant association between periodontitis and salivary CRP concentrations.

alveolar bone with pocket formation, gingival recession or both. Gingivitis is a gum inflammatory disease and clinically the presence of identifiable attachment loss in periodontitis makes it be distinguishable from gingivitis (1).
Host immune response to pathogens such as bacteria in the teeth plaque biofilm is as cooperation of innate and acquired immune system. CRP has given much attention due to its key role in atherosclerosis. So, that if it increases by more than 0.5 milligrams per liter, the risk of cardiovascular diseases increases (2). Several studies have also suggested a correlation between periodontitis and cardiovascular diseases. In some studies, it has even been claimed that there are some correlations between periodontal disease and atherosclerotic heart disease and heart attacks and strokes (2). Although their cause and effect relationship has not been established, but it is likely that elevation of CRP levels in periodontitis may help to understand the relationship between cardiovascular diseases and periodontitis (2).
Several investigations regarding the relationship between salivary CRP levels and periodontal disease have also been done. Among these researches, one can refer to the study of Giannobile et al. in 2009 (4) who showed that the saliva and serum CRP levels were elevated in patients with chronic and aggressive periodontitis.
The purpose of this study was to evaluate salivary CRP levels, clinical attachment loss (CAL), gingival index (GI) and periodontal pocket depth (PPD) indices and the correlation between these indices and CRP saliva levels.

Patients
In this case-control study, the patients referred

Saliva CRP analysis
Firstly, by using spitting method, unstimulated saliva sample was collected from each subject. All patients were asked to avoid eating, drinking, chewing gum, and brushing an hour before collecting samples. They were given sterile capped-tubes and were asked to put 2 mm of their saliva sample into those tubes. Then an evaluation of clinical criteria (CAL), (GI), (PPD) was done.
Barnett method was used to calculate bleeding index. After samples were collected, they were transported to the laboratory and kept under -80 0 C until the day of experiment. The ELISA method (Salimetric kit, USA, code number 1-3302) was used to evaluate salivary CRP level.

Statistical analysis
The collected data were analyzed using statistical software SPSS Version 20 using non-Parametric Kruskal-Wallis and Mann-Whitney test due to abnormal distribution and Spearman correlation coefficient was analyzed. P<0.05 was considered significant.

Discussion
The results of the present study showed that  Our study showed that CRP levels also indicate that diabetes as a metabolic disease, had no effect on salivary CRP levels but the periodontitis due to its inflammatory nature, increases salivary CRP. The results of this study are also in agreement with our findings and others.
According to our data, there is a salivary CRP concentration difference between the healthy subjects and patients with gingivitis, also the difference in concentration between patients with gingivitis and periodontitis was not significant.
However, based on further analysis of the samples, providing a larger sample size, these differences might be significant.
Our study is one of the few studies which compared salivary CRP concentrations in healthy subjects and patients with gingivitis and periodontitis. Based on the findings of our study and the above mentioned studies, it seems that the relationship between periodontal disease and salivery CRP is the same as their relationship with serum CRP. The results of this study shows a significant correlation between salivary CRP levels and severity of periodontal disease. Our study showed that the measurement of salivary CRP can be used as a non-invasive and reliable test for the detection and screening of periodontal disease in healthy people.